Insulation for field windings



March 24, 1931. c. GOAD INSULATION FOR FIELD WINDINGS Filed Dec. 29,1928 Patented Mar. 24, 1931 UNITED STATES PATENT OFFICE LOUIS C. GOAD,OF MUNCIE, INDIANA, ASSIGNOR T0 DELCO-REMY CORPORATION, OF DAYTON, OHIO,A CORPORATION OF DELAWARE INSULATION FOR FIELD WINDING-S Applicationfiled December 29, 1928. Serial No. 329,217.

This invention relates to electric insulation and in particular to amethod of and a blank for insulating a field coil used in dynamicelectric machines.

The object of this invention is to provide a unitary piece of insulationor an insulating jacket for a field coil whereby the cost of productionis greatly reduced by the material reduction of labor and a reduction inthe amount of material used. This is accomplished by cutting from apiece of oiled linen, a blank having a coil shaped body. This coilshaped body has a pair of internal flaps each terminating in a pair oftabs for insulating parts of the inner periphery of the coil and it hasa pair of external extensions for wrapping around the sides of the coilto insulate the sides and to secure the blank to the coil by means ofthe flanges of the T-shaped extensions engaging the coil. As it has beencustomary to insulate the field coils by wrapping tape around the coilit will be readily seen that the cost of production will be greatlyreduced by the saving of the material and labor.

Further objects and advantages of the pres ent invention will beapparent from the following description, reference being had to theaccompanying drawings, wherein a preferred form of embodiment of thepresent invention is clearly shown.

In the drawings:

Fig. 1 shows a blank which has been cut and is ready to be wrappedaround the coil.

Fig. 2 shows a plan view of the field coil, as seen with the convex sideup.

Fig. 3 shows a plan view of the same coil, as seen with the concave sideup.

Fig. 4 shows a sectional view of the coil mounted in the frame andinsulated by this piece of insulating material.

Fig. 5 shows a cross sectional view taken through the ends of the coil.

In the drawings, the reference character 10 indicates an armature of adynamic electric machine. The frame is indicated by the referencecharacter 12 on which is mounted the pole piece 14 by means of a screw13, threadedly engaging the pole piece 14 upon which is mounted a fieldcoil 15. The blank 16 has a pair of dovetail grooves 17 near each endwhich divides the blank 16 into the main body portion 18 and theT-shaped extensions 20. The body portion 18 simulates the shape of thecoil windings, the straight sides 22 corresponding to the ends of thecoil, the bevelled edges 21 corresponding to the rounded corners of thecoil and the portion intermediate the grooves 17 on each endcorresponding to the sides of the coil. In the center, the aperture 25permits the insertion of the core piece 14. This aperture hassubstantially the shape of a T whose stem is connected to a stem of aninverted T as Viewed from one end of the blank 20. Intermediate theflanges 29 of the T and the inverted T and to each side of the stem, arethe flaps 26 terminating in tabs 28. The edges of the flaps 26 arecurved as seen at 30. The coil 15 may be placed over the center of theblank 16 with the convex side of the coil 15 adjacent the blank 16 theaperture 25 coinciding with the center of the coil 15 and the sides '22of the blank 16 coinciding with the ends of the coil 15. l/Vith the coil15 in this position, the flaps 26 are turned inwardly towards the innerperiphery of the coil substantially along the lines 34 so as to form aninsulation for the inner edge of the coil ends 40., tabs 28 being foldedsubstantially at right angles to the flap 26 along the lines 31 so as toreinforce the inner corners of the coil 15. After each of the flaps 26have been turned inwardly and the tabs 28 at rightangles to the flap 26each of the T-shaped ends 20 of the blank 16 are wrapped around thesides of the coil so that the dovetail grooves 17 fit into the innercorners of the coil 15, the flanges 29 of the T-shaped extensions 20extending over the ends of the coil to hold the insulation blank 16 inplace during assembly of the coil 15 on the machine. From this it may bereadily seen that the concave sides of the ends 40 are not insulatedwhich is not necessary for the reason that a pole shoe 36 coil 15, theseinsulate the sides of the coil 15 from the pole shoes 36 and the core ofthe pole piece 14: and also insulates the coil 15 from the frame 12. Thesides 22 of the blank 16 insulate the ends i0 of the coil 15 from theframe v1E2. Fromthis it may be readily seen that Wherever the coil 15comes-in contact with metallic parts of the machine, the blank insulatesthese parts from the coil 15.

WVhile the form of embodiment of the present invention as, hereindisclosed, constitutes a preferred form, it is to be understood thatother forms might be adopted, all coming within the scope of the claimswhich follow.

What is claimed is as follows:

1. A blank of insulating material for a coil, having substantially theshape of the coil with internal flaps to insulate the inner edge of theends of the coil, each of said flaps 1 terminating ina pair of tabs forreinforcing the'insu'lation around the inner corners of the coil andhaving external extensions for wrapping around the sides of the coil tocompletely insulate the sides 01 the coil and to secure the blank tothe'coil.

2. A blank of insulating material for a field coil having substantiallythe shape of the coil, said blank having extensions for wrapping aroundthe coil to insulate part of the coil, said extensions holding the blankon the coil when wrapped. around the coil.

3. A blank of insulating sheet material for a field coil having aninternal flap for insulating part of the coil and an external T- shapedextension for insulating part of the coil said T-shaped extensionholding the blank in position.

4; A blank of insulating sheet material for a field coil havingsubstantially a coil shaped body with a pair of external T-shapedextensions extending from the sides ofthe coil shaped body and a pair ofinternal flaps extending along the inner ends of the coil, the flapsforming the insulation for the inner edge of the ends of the coil, said'fiaps terminating in tabs for insulating and reinfor'cing the innercorners of said coil.

5. An'i'nsula'ted field coil comprising, in combination, a plurality ofwindings, and an insulating jacket, said insulating jacket having a bodyportion for insulating the convex side ofthe coil, having flaps forinsulating the inner edges of the ends of said coil, said flapsterminating in tabs for insulating the inner corners of said coil andhaving T- shapedextensions for wrapping around the sides ofsaid coil tocompletely insulate the sides, the insulating jacket being held on thecoil by the flanges of the Tshaped extensions passing through the centerof said coil locking the extensions.

In testimony whereof I hereto affix my signature.

LOUIS o. G'OAD.

